Ruth Madoff flew from Florida to Greenwich, Conn., to attend a private memorial service for her son Mark after his suicide last December — but was turned away by his unforgiving widow, Stephanie.

The first lady of fraud mourned at a friend’s house and sat shiva alone, a family source told People magazine. She passes most of her days and nights alone and numb, the friend said.

“She told me, ‘At night, it gets to me — the shame, the disgrace, all the stuff that killed Mark.’ ”

When Bernard Madoff’s Ponzi scheme collapsed, Mark and his brother, Andrew, warned their mother: It’s him or us.

Ruth, 69, chose her cherished sons, the source said — until Bernie Madoff was beaten in prison in 2009. She returned to the 72-year-old swindler’s side, infuriating the two sons, who cut her out of their lives.

The magazine says Ruth hides behind her maiden name, Alpern, and dyes her hair red when venturing out to rent dollar DVDs or visit the public library.

“If Ruth were able to feel that pain, in the magnitude that it’s actually there, I don’t know that she wouldn’t do what Mark wound up doing,” the friend said.